Crankcase ventilator



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CRANKGASE VENTILATOR File@ May 14, 193e. y

l INVENTOR. LEQNABD D.. Bovo;

I conditions.

UNITED STATES l PATENT 'f OFFICE `A oRaNKcAsE VENTILATon Leonard D. Boyce, Maplewood, Mo. Application May 14, ms, serial No. '19,723

(ci. 12s- 119) 3 Claims.

This invention relates to Ventilating systems for internal combustion engines and consists particularly in means'for drawing fumes from the engine crank case through the fuel intake passages by suction. .v

In warm weather the oil in automobile crank cases vaporizes substantially creating fumes which frequently escape into the passenger space 10 of the vehicle, causing unpleasantness and discomfort. In cold weather, vaporization of the Aoil may be sumtantially reduced but at such times gasoline and moisture mix with the oil causing dilution and forming sludge. Ventilation of the crank case space will substantially, reduce or eliminate the undesirable effects of both of these The main object of the present invention is to provide novel means for conditioning or ventilating the crank engine.

A more detailed object is to provide means for drawing o and disposing of nauseating fumes arising from the crank case, particularly in warm Weather.

Another object is to provide novel means for drawing on gasoline and Water vapors from the crank case, which would otherwise tend to condense and mix with the oil, diluting the same and forming sludge. 4

Still another object is'to provide novel means for injectingoily fumes into the engine intake manifold, to provide upper cylinder and valve lubrication. I'hese objects and other more detailed objects hereafter appearing are attained substantially by the structure illustrated in the accompanying drawing in which:

Figure 1 is a side view of a portion of an internal combustion engine and carburetor embodying the invention, the carburetor being sectioned.

Figure 2 is a substantially horizontal section and top view of a part of the structure in Figure l and taken on line 2-2 thereof.

Figure 3 is a vertical transverse detail section taken on the line 3 3 of Figure 2.

Figure 4 is a partial vertical section taken substantially on line 4"-4 of Figure 1. l

Figure 1 illustrates a downdraft carburetor including a mixture passage having an air inlet horn I, vventuri 2, and an outlet portion' 3. Pivoted on shaft 5 in the air horn is a choke valve 6, and throttlevalve 'I is pivoted on shaft 8 near the lower portion of thecarburetori rSuitable control means (not shown) are ating the choke and throttle case of an internalcombustion adjacent the mixture passage has a float Il con-` provided for. opertrolling" needle valve II in inlet connection IIa" se as to maintain fuel within the bowl at a substantially constant level. Fuel is supplied through main nozzle A and idling passage B, both conventional. l 5 Located beneath the carburetor is an intake manifold I2 constituting'a Yfuel intake passage andexhaust manifold I3 which may be conveniently formed, as shown, in a combined structure having a flanged riser portion I4. Inserted 1 between riser I4 and outlet 3 of the carburetor is a collar member I5 having a'iitting I6 connected by nipple I'l to a conduit I8 which extends down- Wardly into the. usual crank case, a portion of which is shown at I9. A heat insulating gasket 17 I5a may be inserted between the collar member and the carburetor.

Collar member I5 includes a centrally hollowed body portion forming'a part of the carburetor mixture passage' and communicating throughorifice 20 with a horizontal tchamber or cylinder 2l, one portion of which communicates withy the mixture passage beneath the throttle through a.y passage 22 and the opposite portionof which communicates with the mixture passage above the throttle through a passage 23.

Received for reciprocation within cylinder 2I is a piston-type valvemember including portions 2li and 25 connected by stem 26. Portions 24 and 25 are cup-shaped and receive coiled springs 21 29 at one end of cylinder 2| and wall 30 at the other end thereof. The side Wall of portion 24 of the valve member is of unbroken, cylindrical shape and the wall of portion 25 has a central,` annular recess-3L 3 Springs 21 and 28 are calibrated so that-when the engine is at rest, and during the cranking period when the depression beneath ,the throttle does not. substantially exceed a halfA inch of mercury,`the piston valve member will be in a position as shown in Figure 2 with portion 24 thereof `sealing orifice 20and cutting oi communication between ventilator 'conduit I8 'and the interior of Vmi' 2 l' 2,1s9,so1

' As the suction -within the mixture passage equalizes, due to opening of the throttle, the valve member will be moved toward wall 30 opposite plug 29 and immediately suction will be ,communicated to conduit I8 through the space between portions 24 and 25 of the valve member, causing fumes and vapors to be drawn through the intake manifold and passed out through the exhaust ports. Under normal operating conditions, the valve member will be substantially centered relative to'oriflce 20, as shown in Figure 3. Even under lowest operating suction conditions, as for instance when the throttle is fully opened and the engine moving slowly under a heavy load, a portion of orifice 20 will be open, permitting crank case ventilation. I

The two springs 2l and 28 are provided to stabilize the valve member, particularly during low suction periods. Spring 21 is preferably slightly stronger than spring 28 so as to urg'e the valve member to the position shown in Figure 2 when the pressures above and below the throttle are substantially equal. Collar member I5, being directly in engagement'with themanifold riser, is l heated substantially to the same extent as the manifold, and this prevents condensation and freezing of moisture adjacent the valve member and in orice 20.

Obviously the Ventilating effect produced under y different operative conditions may be varied by altering the sizeof orifice 2B and passages 22 and 23, the shape of the valve member, or the relative strengths of springs 21 and 28. The Ventilating .conduit isshown in communication with the intake passage beneath the throttle in such a position that oily fumes drawn through the intake manifold can function as upper cylinder and valve lubrication. This particular location ofthe venti- Alatirlg conduit connection with the mixture passage is not essential and, if desired, this conduit may communicate with the carburetor above the throttle or with another portion of the intake system. The valve member may be conveniently controlled, as shown, by relative pressures on the opposite sides of the throttle valve. This is likewise, not essential and the Ventilating control may be effected by differences in pressure between any convenient portion of the intake system and the crank case, or other parts of the intake passage. Also the novel Ventilating mechanism may be advantageously utilized where 'a space other than the crank case is to be conditioned.

These modifications and others may be made in the illustrated structure,` as will occur to those skilled in the art, Without departing from the spirit of theinvention and the exclusive use of all such modcations as come within the scope of the appended claims is contemplated.

I claim:

l. In an internal combustion engine, a walled space to be ventilated, a fuel intake passage including a carburetor throttle valve, a conduit connecting said space and said passage and including a chamber, a valve member in said chamber, and suction connections between said' chamber and portions of said passage immediately on opposite sides of said throttle valve.

2. In an 'internalcombustion engine, an intake passage, a walled space to be ventilated, a conduit connecting said space and said passage, a cylinder communicating with said conduit, and a springloaded, suction-controlled piston in said cylinder having a portion constructed and arranged to close said conduit when suction in said passage is no greater than cranking suction, said 'piston havinga bypass recess positioned to permit rela-` tively slight bleeding of suction past said piston at periods of greatest suction in said passage.y

3,. In an internal combustion engine, an intake passage, a walled-space to be ventilated, a conduit connecting said space and said passage, a cylinder communicating with said conduit, and a springloaded, suction controlled piston in said cylinder, having a portion constructed and arranged to close said conduit when suction in said passage is no greater than cranking suction, said piston also having a by-pass recess positioned to permit relatively slight bleeding of suction past said piston at periods of high. suction in said'passage, and a part between said portion and said recess positioned to permit substantially full communication through said conduit during normal, open throttle operation of the engine.

LEONARD D. BOYCE. 

